This is the sizing chart:
Height (cm) | S | M | L | XL |
---|
Height (cm) | 170 - 179 | 177 - 183 | 181 - 189 | 187 - 195 |
Inside Leg (cm) | 74 - 82 | 78 - 85 | 82 - 89 | 86 - 94 |
i'm 6ft5 but 34" inside leg (or 195cm and 86cm) so ride an XL. If they'd offered an XXL I'd have probably gone for that but mainly to get a bit of extra length, not that the upper sizes always give you that, it's often just a little bit of extra height.
So assuming your inside leg is 30" or more and you don't mind more of a stretch position the Medium sounds about right, you might be a bit squashed on a small.
I'm not sure what I'd upgrade on it, certainly not before anything wore out. Possibly compressionless cable housing for the brakes but the brakes are fine. I fitted my favourite saddle on it but that's just a personal thing, the stock saddle is not dissimilar to a Fabric Scoop, which most people seem to get on with.